This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Baker, D. G. Search for Related Content PubMed PubMed Citation Articles by Baker, D. G.

Influence of a Chronic Environmental Stress on the Incidence of Methylcholanthrene-induced Tumors¹

Claire Zellerbach Saroni Tumor Institute, Mount Zion Hospital and Medical Center, San Francisco, California 94115

The influence of a chronic environmental stress, living in a 2° environment, on the incidence of methylcholanthrene-induced tumors in albino female Simonsen rats, a Sprague-Dawley-derived strain, was studied. The results indicated that the metabolic rate was double for rats kept at 2°, compared with those kept at 25°. Exposure to 2° for life, with no other treatment, reduced median life expectancy to 560 days compared with 686 days for rats kept at 25°. Transfer to a 2° environment after 250 days at 25° reduced the incidence of spontaneous tumors, while transfer to 25° after 250 days at 2° increased the incidence of tumors compared to that for rats always kept at 25°. Exposure to an environmental temperature of 2° immediately following a carcinogenic stimulus (3-methylcholanthrene, 2 mg s.c.) significantly reduced the incidence of tumors compared to that in rats kept at 25° but did not change tumor induction time. The reduced tumor incidence may have resulted from inhibition of the carcinogenic transformation by chronic stress. The survival time of rats with 3-methylcholanthrene-induced tumors was not significantly less in a 2° environment than it was at 25°.

¹ Supported in part by NIH Radiation Oncology Research Training Grant CA05203, USPHS General Research Support Grant RR05472, and General Research Funds from the Mount Zion Hospital and Medical Center, San Francisco, Calif.

Received 5/12/77. Accepted 7/27/77.